<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>数据类型</title>
</head>
<body>
    
</body>
</html>
<script>
    //使用typeof判断数据的类型
    // let a = 1;
    // console.log(typeof a)
    // let b = "1";
    // console.log(typeof b)
    // //未赋值或者不存在的变量返回underfind
    // var hd;
    // console.log(typeof hd)
    // console.log(typeof aa)

    // //方法返回function
    // function run(){}
    // console.log(typeof run)

    // let c = [1,2,3];
    // console.log(typeof c)

    // let d = {name:"houdunren.com"};
    // console.log(typeof d)

    //instanceof   
    // let hd = [];
    // let houdunren = {};
    // console.log(hd instanceof Array)
    // console.log(hd instanceof Object)
    // console.log(houdunren instanceof Array)
    // console.log(houdunren instanceof Object)

    // let c = [1,2,3];
    // console.log(c instanceof Array)

    // let d = {name:"houdunren.com"}
    // console.log(d instanceof Object)

    // function User(){}
    // let hds = new User();
    // console.log(hds instanceof User) 

</script>